JP2006006777A - X-ray ct apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray CT apparatus with improved strength of mounting X-ray detecting elements. <P>SOLUTION: An X-ray detecting means 7 is formed with a plurality of X-ray detecting elements 7a continuously arranged on a circular arc around an X-ray irradiation point 6a of an X-ray irradiation means 6. The X-ray detecting means 7 consists of a polygonal frame 13 in a similar circular arc shape around the X-ray irradiation point 6a, a mounting frame 12 to which the polygonal frame 13 is attached, and a support member 14 mounted on the back side of the X-ray detecting elements for fixing the X-ray detecting elements 7a to the mounting frame 12 with one end side of each X-ray detecting element 7a clasped between the mounting frame 12 and the polygonal frame 13. Since the X-ray detecting elements 7a are firmly fixed to the mounting frame 12 by the support member 14, an artifact will not be generated in an X-ray image detected by the X-ray detecting elements 7a even if large centrifugal force is applied to the X-ray detecting elements 7a while a rotary body 4 is rotated, and furthermore, breakage of the X-ray detecting elements themselves can be prevented. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an X-ray CT apparatus with improved attachment strength of an X-ray detection element.

Conventionally, as this type of X-ray CT apparatus, for example, the one described in Patent Document 1 is known.
The X-ray CT apparatus described in Patent Document 1 is arranged such that an X-ray irradiation point and an X-ray are arranged so as to face a rotating body that rotates about the body axis of a subject placed on a top plate with the subject interposed therebetween. A line detector is provided.
As the rotating body rotates, the subject is irradiated with X-rays from the X-ray irradiation point, and the X-ray detected by the X-ray transmitted through the subject is curved in an arc around the X-ray irradiation point. The electric signal received by the detector is converted into an electric signal according to the X-ray intensity, and the electric signal output from the X-ray detector is amplified to a value of an appropriate level and then subjected to arithmetic processing by an arithmetic processing unit to be processed. A tomographic image of the specimen is reconstructed, and the reconstructed tomographic image is displayed on the display device.

For example, as shown in FIG. 7, an X-ray detector used in a conventional X-ray CT apparatus has a plurality of X-ray detection elements a arranged in one or more rows on an arc centered on an X-ray irradiation point. The X-ray detection element a has an approximately arc-shaped channel arrangement that is continuously arranged and fixed between a pair of polygonal frames b and c that are curved around the X-ray irradiation point. It has become.
Further, the X-ray detector needs to efficiently make X-rays incident from the front face incident on the X-ray incident part of the X-ray detection element a, and at the same time, scattered X-rays from the subject are detected by the X-ray detection element a. In order to prevent the X-ray detection element a from being incident on the X-ray detection element a, the polygonal frames b and c are arranged so as to sandwich the X-ray incidence part of the X-ray detection element a. e is fixed to each of the polygonal frames b and c, and a spacer f is interposed between both ends of each of the polygonal frames b and c to keep the distance between them constant.
JP 2003-98261 A

However, the conventional X-ray detector has a configuration in which spacers f are interposed only between both ends of each of the polygonal frames b and c in order to make X-rays transmitted through the subject efficiently enter the X-ray detection element a. It has become.
For this reason, when the rotating body is rotated to perform X-ray imaging, one polygonal frame b supported only at both ends by the spacer f is deformed by the centrifugal force applied to the X-ray detection element a. The X-ray detection element “a” attached to is in an unstable state.
In particular, in recent X-ray CT apparatuses, in order to obtain a clear X-ray tomographic image, a rotating body is rotated at a high speed to perform X-ray imaging, so that a centrifugal force applied to the polygonal frames b and c and the X-ray detection element a is applied. As a result, the polygon frame b is deformed, resulting in artifacts in the image detected by the X-ray detection element a, and damage to the X-ray detection element a itself.
The X-ray detection element a is provided with temperature adjusting means for controlling the temperature. However, since the X-ray detection element a is divided in the arc direction of the polygonal frame, the X-ray detection element a is provided for each X-ray detection element a. In addition to controlling the temperature and preventing local thermal deformation of the polygonal frames b and c, there is a need for an expensive temperature adjusting means with little bias or fluctuation in the temperature distribution, which increases the cost of parts. There is also.

  The present invention has been made in order to improve such a conventional problem, and an object of the present invention is to provide an X-ray CT apparatus in which the attachment strength of the X-ray detection element is improved.

  In the X-ray CT apparatus of the present invention, an X-ray irradiating means and an X-ray detecting means arranged opposite to each other with a subject interposed therebetween are installed on a rotating body that rotates about the body axis of the subject, and X-ray detection is performed. An X-ray CT apparatus formed by continuously arranging a plurality of X-ray detection elements on an arc centered on an X-ray irradiation point of the X-ray irradiation means, wherein the X-ray detection means A polygonal frame formed in an approximate arc shape around the X-ray irradiation point, a mounting frame provided with the polygonal frame, a polygonal frame attached to the back side of the X-ray detection element, and The X-ray detection element is fixed to the mounting frame in a state where one end side of the X-ray detection element is sandwiched between the support members.

With the above configuration, when a rotating body is rotated at a high speed in order to obtain a high-resolution tomographic image, each X-ray detection element is supported even if a large centrifugal force acts on each X-ray detection element of the X-ray detection means. Since it is firmly fixed to the mounting frame by the member and is not affected by the deformation of the polygonal frame, no artifact is generated in the X-ray image detected by the X-ray detection element, and X-ray detection is performed. Since the mounting strength of the element is remarkably improved, the X-ray detection element itself can be prevented from being damaged.
In addition, since it is not necessary to prevent local thermal deformation of the polygonal frame, an expensive temperature controller with little unevenness and fluctuation in temperature distribution is not required, thereby reducing the cost of the X-ray detection means.

  The X-ray CT apparatus of the present invention is provided with a light-shielding frame formed in an arc shape centering on an X-ray irradiation point at a position facing the mounting frame across the X-ray incident part of the X-ray detection element. is there.

  With the above configuration, scattered X-rays from the subject are blocked by the attachment frame and the light-shielding frame and do not enter the X-ray incident portion, so that a clear X-ray tomographic image that is not affected by the scattered X-rays is obtained. Be able to.

  In the X-ray CT apparatus of the present invention, the support member is formed so that the attachment surface of the X-ray detection element and the attachment surface of the attachment frame are at right angles.

  With the above configuration, each X-ray detection element can be accurately fixed to the attachment frame by attaching the support member to which the X-ray detection element is attached in advance to the attachment frame. As well as improving the work efficiency during assembly.

  According to the X-ray CT apparatus of the present invention, each X-ray detection element is firmly fixed to the mounting frame by the support member. Therefore, even when the rotating body is rotated at a high speed, X detected by the X-ray detection element Artifacts do not occur in the line image, and the attachment strength of the X-ray detection element is remarkably improved, so that the X-ray detection element itself can be prevented from being damaged.

Embodiments of the present invention will be described in detail with reference to the drawings.
1 is a perspective view showing the inside of the X-ray CT apparatus, FIG. 2 is a perspective view of the upper surface side of the X-ray detection means, FIG. 3 is a perspective view of the lower surface side, and FIG. 4 is an X-ray detection element and an amplification circuit module. FIG. 5 is a perspective view of the assembled state of the X-ray detection element and the support member, and FIG. 6 is a perspective view of the support member.
The apparatus main body 1 of the X-ray CT apparatus shown in FIG. 1 is provided with a circular opening 1b that opens in the horizontal direction at a substantially central portion of a scanner cover 1a formed in a box shape. The top plate 2 is provided so as to be freely inserted into and removed from the opening 1b.
The top 2 is horizontally installed so that the subject 3 to be X-rayed can be placed in a lying state, and can be moved in the horizontal direction in synchronization with the rotation of the rotating body 4 by a moving means (not shown). ing.

In the scanner cover 1a, a rotating body 4 having a circular hole 4a opened at the center is supported so as to be rotatable about the body axis of the subject 3 on the top plate 2.
The rotating body 4 is rotated by a rotary drive source 5 made of an electric motor. The X-ray irradiating means 6 and the X-ray detection are provided on one surface of the rotating body 4 at a position facing each other across the circular hole 4a. Means 7 are attached.
The X-ray irradiation means 6 has an X-ray irradiation point (focal point) 6a that irradiates X-rays toward the subject 3 on the top 2 and the X-rays 8 irradiated from the X-ray irradiation point 6a are After the X-ray dose is adjusted by the compensation filter 9b provided in the filter case 9a of the filter means 9, the X-ray collimator 10 reduces the X-ray dose to a predetermined thickness so that the subject 3 is irradiated. .

As shown in FIGS. 2 and 3, the X-ray detection means 7 that receives the X-ray 8 that has passed through the subject 3 includes an attachment frame 12 that is fixed to one surface of the rotating body 4, and a spacer on the attachment frame 12. An arc-shaped shading frame 11 supported at both ends via 11a is provided.
The mounting frame 12 is a plate formed in an arc shape centering on the X-ray irradiation point 6a of the X-ray irradiation means 6, and the polygon frame 13 is fixed to the surface opposite to the mounting surface side of the rotating body 4. Has been.
The polygon frame 13 is also formed in an arc shape centered on the X-ray irradiation point 6a of the X-ray irradiation means 6, and the mounting surface 13a of the X-ray detection element 7a constituting the X-ray detection means 7 is polygonal. Thus, the channel arrangement in which the X-ray detection element a is approximately arc-shaped is possible.
The X-ray detection means 7 is composed of a plurality of X-ray detection elements 7a divided in a large number in the arc direction of the polygonal frame 13, and one of the X-ray detection elements 7a is a strip as shown in FIG. An X-ray incident part 7 b is formed on the surface facing the X-ray irradiation means 6.
Mounting holes 7c are formed in the middle of one end side of the X-ray detection element 7a, and these mounting holes 7c are aligned with screw holes 14a formed in both end sides of the support member 14. Yes.

The support member 14 is for fixing the X-ray detection element 7a to the mounting frame 12 with high accuracy. The support member 14 is provided for each X-ray detection element 7a and is substantially L-shaped with one end bent as shown in FIG. The X-ray detection element mounting surface 14e and the mounting frame mounting surface 14f of the support member 14 are at right angles, and a fixing tool 22 for fixing the support member 14 to the mounting frame 12 is provided at the bent portion 14b. A mounting hole 14c for insertion is formed.
On the X-ray detection element mounting surface 14e of the support member 14, mounting seats 14d are formed at the drilled portions of the screw holes 14a. The mounting seat 14d is in contact with one end side of the X-ray detection element 7a and a substantially intermediate portion. The X-ray detection element 7a is inserted into the support member 14 by screwing a fixing tool 23 such as a screw inserted through the attachment hole 7b of the X-ray detection element 7a into the screw hole 14a of the support member 14 in the contact state. It is fixed as shown in FIG.

  The support member 14 to which the X-ray detection element 7 a is attached detects the X-ray of the polygonal frame 13 by screwing the fixing tool 22 inserted from the attachment hole 14 c of the bent portion 14 b into the screw hole 12 a of the attachment frame 12. The X-ray detection element 7a and the support member 14 are fixed to the attachment frame 12 in a state where one end side of the X-ray detection element 7a is tightly attached between the element attachment surface 13a and the attachment seat 14d of the support member 14. On the X-ray detection element mounting surface 13a of the polygon frame 13, a recess 13b is formed so that the head of the fixture 23 that fixes the X-ray detection element 7a to the support member 14 and the polygon frame 13 do not interfere with each other. ing.

In the X-ray detection element 7a attached to the attachment frame 12 by the support member 14 as described above, the X-ray detection element attachment surface 14e and the attachment frame attachment surface 14f of the support member 14 are formed at right angles in advance. The X-ray detection elements 7a can be fixed at right angles with respect to the mounting frame with high accuracy, and each X-ray detection element 7a is connected to each amplification circuit module 15a of the amplification means 15 installed in the vicinity of the X-ray detection means 7 by a cable such as a flexible cable. 16 is connected.
The amplification means 15 is for amplifying the signal detected by the X-ray detection element 7a to an appropriate level, and is composed of a plurality of amplification circuit modules 15a provided for each X-ray detection element 7a.

The light-shielding frame 11 having both ends attached to the attachment frame 12 via the spacer 11a is formed in an arc shape centering on the X-ray irradiation point 6a of the X-ray irradiation means 6, and is scattered X from the subject 3. By blocking the line from the attachment frame 12, the scattered X-rays are prevented from entering the X-ray incident part 7b of the X-ray detection element 7a. A cooling means 17 for efficiently cooling the heat generated by the means 6 is attached to the rotating body 4.
A power supply 18 for supplying power to the X-ray irradiation means 6 and a transformer 19 are attached to the rotary body 4 at positions facing each other across the circular hole 4a of the rotary body 4. The cooling means 17, the power supply 18 and The transformer 19 is configured to rotate integrally with the rotating body 4, and a control unit 20 that controls the entire apparatus is installed at, for example, an upper corner portion in the scanner case 1 a. An operation console (not shown) and image processing means are connected to 20 via an interface (both not shown).

Next, the operation of the X-ray CT apparatus constructed as described above will be described.
When the operation of the apparatus main body 1 is started with the subject 3 lying on the top 2 that has stopped at the position retracted from the opening 1b of the apparatus main body 1, the rotating body 4 starts to rotate within the scanner case 1a. At the same time, the top plate 2 is moved horizontally toward the opening 1b in synchronization with the rotation of the rotating body 4.
Further, X-rays 8 are irradiated from the X-ray irradiation point 6a of the X-ray irradiation means 6 toward the subject 3, and the X-rays 8 reach the subject 3 through the filter means 9 and the X-ray collimator 10, The X-ray 8 that has passed through the subject 3 is received by the X-ray detection means 7 disposed so as to face the X-ray irradiation means 6 with the subject 3 interposed therebetween, and is detected by the X-ray detection element 7a according to the X-ray intensity. Converted into an electrical signal.
The electrical signal output from the X-ray detection element 7a is sent to the amplifying means 15 via the cable 16, amplified to an appropriate level by each amplifier circuit module 15a of the amplifying means 15, and then sent to the control means 20, The tomographic image of the subject 3 is reconstructed by calculation processing by the image processing means provided in the control means 20, and the reconstructed tomographic image is displayed on a display means (not shown).

On the other hand, when the rotating body 4 is rotated at a high speed in order to obtain a high-resolution tomographic image, a large centrifugal force acts on each X-ray detection element 7a of the X-ray detection means 7, but each X-ray detection element 7a is supported by a support member. 14 is firmly fixed to the mounting frame 12 and the conventional polygon frame for fixing the intermediate portion of the X-ray detection element 7a is abolished, so that the X war detection element 7a is affected by the deformation of the polygon frame. Therefore, no artifact is generated in the X-ray image detected by the X-ray detection element 7a.
Further, the X-ray detection element 7a generated by the deformation of the polygonal frame is not damaged, and it is not necessary to prevent the local thermal deformation of the polygonal frame. An adjuster is not necessary, and the cost of the X-ray detection means 7 can be reduced.

  In the X-ray CT apparatus of the present invention, each X-ray detection element is firmly fixed to the mounting frame by the support member, so that no artifact is generated in the X-ray image detected by the X-ray detection element, Since the attachment strength of the X-ray detection means is remarkably improved, it is optimal for an X-ray CT apparatus that performs X-ray tomography by rotating the rotating body at a high speed.

It is a perspective view which shows the inside of the X-ray CT apparatus which becomes embodiment of this invention. It is a perspective view of the upper surface side of the X-ray detection means provided in the X-ray CT apparatus which becomes embodiment of this invention. It is a perspective view of the lower surface side of the X-ray detection means provided in the X-ray CT apparatus which becomes embodiment of this invention. It is a perspective view which shows the X-ray detection element and amplification circuit module of the X-ray detection means provided in the X-ray CT apparatus which becomes embodiment of this invention. It is a perspective view which shows the assembly state of the X-ray detection element and support member of the X-ray detection means provided in the X-ray CT apparatus which becomes embodiment of this invention. It is a perspective view which shows the support member of the X-ray detection means provided in the X-ray CT apparatus which becomes embodiment of this invention. It is a perspective view of the lower surface side of the X-ray detection means provided in the conventional X-ray CT apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Apparatus main body 3 Subject 4 Rotating body 6 X-ray irradiation means 6a X-ray irradiation point 7 X-ray detection means 7a X-ray detection element 11 Light-shielding frame 12 Mounting frame 14 Support member 14e X-ray detection element mounting surface 14f Mounting frame mounting surface

Claims (3)

  An X-ray irradiating means and an X-ray detecting means arranged opposite to each other with the subject interposed therebetween are installed on a rotating body that rotates about the body axis of the subject, and the X-ray detecting means is used as the X-ray irradiating means. An X-ray CT apparatus formed by continuously arranging a plurality of X-ray detection elements on an arc centered on an X-ray irradiation point of the means, wherein the X-ray detection means A polygonal frame formed in an approximate arc shape centered on a point; an attachment frame provided with the polygonal frame; a polygonal frame attached to the back side of the X-ray detection element; An X-ray CT apparatus comprising: a support member that fixes the X-ray detection element to the mounting frame with one end of the X-ray detection element sandwiched therebetween.   The X-ray according to claim 1, wherein a light shielding frame formed in an arc shape centering on the X-ray irradiation point is provided at a position facing the mounting frame across an X-ray incident portion of the X-ray detection element. Line CT device. The X-ray CT apparatus according to claim 1, wherein the support member is formed so that an attachment surface of the X-ray detection element and an attachment surface of the attachment frame are perpendicular to each other.

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